1. Field of the Invention
The present invention relates to a vehicle that includes a body frame that can lean and two front wheels.
2. Description of the Related Art
A known vehicle includes a body frame that leans to the left or right when the vehicle is cornering and two front wheels that are aligned in a left-and-right direction of the body frame (for example, refer to Japanese Patent Unexamined Publication JP-A-2005-313876, U.S. Design Pat. D547,2425 and Catalogo partidi ricambio, MP3 300 64102 ie LT Mod. ZAPM64102, Piaggio).
The vehicle including the body frame that can lean and two front wheels includes a link mechanism. The link mechanism includes an upper cross portion and a lower cross portion. In addition, the link mechanism also includes a right side portion which supports right end portions of the upper cross portion and the lower cross portion and a left side portion which supports left end portions of the upper cross portion and the lower cross portion. Middle portions of the upper cross portion and the lower cross portion are supported on the body frame at the front of a steering shaft. The upper cross portion and the lower cross portion are supported on the body frame so as to turn about axes that extend substantially in a front-and-rear direction of the body frame. The upper cross portion and the lower cross portion turn relative to the body frame as the body frame leans. Then, a relative position of the two front wheels in an up-and-down direction of the body frame changes. The upper cross portion and the lower cross portion are provided above the two front wheels in the up-and-down direction of the body frame when the body frame rests in an upright state.
The vehicle including the body frame that can lean and two front wheels includes a right shock absorbing device which supports the right front wheel so as to move in the up-and-down direction of the body frame and a left shock absorbing device which supports the left front wheel so as to move in the up-and-down direction of the body frame. The right shock absorbing device is supported on the right side portion so as to turn about an axis of the right side portion. The left shock absorbing device is supported on the left side portion so as to turn about an axis of the left side portion. Vehicles described in Japanese Patent Unexamined Publication JP-A-2005-313876 and U.S. Design Pat. D547,2425 include further a handlebar, a steering shaft, and a turn transfer mechanism. The handlebar is fixed to the steering shaft. The steering shaft is turnably supported on the body frame relative thereto. Turning the handlebar turns the steering shaft. The turn transfer mechanism transfers the turning motion of the steering shaft to the right shock absorbing device and the left shock absorbing device.
The vehicle including the body frame that can lean and two front wheels includes many on-board components which are provided on the periphery of the steering shaft. The on-board components include lamps such as a headlamp, a radiator, a reservoir tank, electric components such as a horn, and a main switch of the vehicle, a storage box, a storage pocket and the like.
In the vehicles described in Japanese Patent Unexamined Publication JP-A-2005-313876 and U.S. Design Pat. D547,2425, loads that are received by the right front wheel and the left front wheel are transferred to the link mechanism by the right shock absorbing device or the left shock absorbing device. The loads are transferred to the right side portion or the left side portion from the right shock absorbing device or the left shock absorbing device. The loads are transferred to the upper cross portion and the lower cross portion from the right side portion or the left side portion. The loads are transferred further to the body frame that is positioned on the periphery of the steering shaft from the upper cross portion and the lower cross portion. The link mechanism includes bearings provided between the right side portion or the left side portion and the upper cross portion and the lower cross portion and bearings provided between the upper cross portion and the lower cross portion and the body frame. These bearings function to enable the right side portion or the left side portion to turn smoothly relative to the upper cross portion and the lower cross portion and the upper cross portion and the lower cross portion to turn smoothly relative to the body frame. The bearings also function to transfer the loads received by the link mechanism to the body frame. Additionally, the right side portion, the left side portion, the upper cross portion, and the lower cross portion are each highly rigid in order to enhance the function to rotate smoothly and the function to transfer the loads. This enlarges the right side portion, the left side portion, the upper cross portion, and the lower cross portion in external size. This results in enlargement of the link mechanism that includes those portions. The enlargement of the link mechanism results in a further expansion of the movable range of the link mechanism.
The vehicles described in Japanese Patent Unexamined Publication JP-A-2005-313876 and U.S. Design Pat. D547,2425 include the link mechanism provided on the periphery of the steering shaft so as to move as the body frame leans. Because of this, in the vehicle including the body frame that can lean and two front wheels, the on-board components need to be provided so that the on-board components do not interfere with the movable range of the link mechanism. In the vehicle that includes the body frame that can lean and two front wheels, this requirement tends to increase the construction on the periphery of the steering shaft.